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1、二甲醚清潔燃料均質(zhì)壓燃燃燒數(shù)值模擬研究畢業(yè)設(shè)計(jì)(論文)題目,黑體小五號字。二甲醚清潔燃料均質(zhì)壓燃燃燒數(shù)值模擬研究中文題目,三號黑體居中,上下各空一行。四號黑體摘要正文五號宋體,首行縮進(jìn)二個(gè)字,單倍行距。300-500字??找恍姓|(zhì)充量壓縮著火(HCCI)燃燒,作為一種能有效實(shí)現(xiàn)高效低污染的燃燒方式,能夠使發(fā)動(dòng)機(jī)同時(shí)保持較高的燃油經(jīng)濟(jì)性和動(dòng)力性能,而且能有效降低發(fā)動(dòng)機(jī)的NOx和碳煙排放。此外HCCI燃燒的一個(gè)顯著特點(diǎn)是燃料的著火時(shí)刻和燃燒過程主要受化學(xué)動(dòng)力學(xué)控制,基于這個(gè)特點(diǎn),發(fā)動(dòng)機(jī)結(jié)構(gòu)參數(shù)和工況的改變將顯著地影響著HCCI發(fā)動(dòng)機(jī)的著火和燃燒過程。本文以新型發(fā)動(dòng)機(jī)代用燃料二甲醚(DME)為例
2、,對HCCI發(fā)動(dòng)機(jī)燃用DME的著火和燃燒過程進(jìn)行了研究。研究采用由美國LawrenceLivermore國家實(shí)驗(yàn)室提出的DME詳細(xì)化學(xué)動(dòng)力學(xué)反應(yīng)機(jī)理及其開發(fā)的HCT化學(xué)動(dòng)力學(xué)程序,且DME的詳細(xì)氧化機(jī)理包括399個(gè)基元反應(yīng),涉及79個(gè)組分。為考慮壁面?zhèn)鳠岬挠绊?,在HCT程序中增加了壁面?zhèn)鳠嶙幽P?。采用該方法研究了壓縮比、燃空當(dāng)量比、進(jìn)氣充量加熱、發(fā)動(dòng)機(jī)轉(zhuǎn)速、EGR和燃料添加劑等因素對HCCI著火和燃燒的影響。結(jié)果表明,DME的HCCI燃燒過程有明顯的低溫反應(yīng)放熱和高溫反應(yīng)放熱兩階段;增大壓縮比、燃空當(dāng)量比、提高進(jìn)氣充量溫度、添加H2O2、H2、CO使著火提前;提高發(fā)動(dòng)機(jī)轉(zhuǎn)速、采用冷卻EGR、添
3、加CH4、CH3OH使著火滯后??找恍嘘P(guān)鍵詞:均質(zhì)充量壓縮著火,化學(xué)動(dòng)力學(xué),數(shù)值模擬,二甲醚,EGR五號宋體,逗號分開,最后一個(gè)關(guān)鍵字后面無標(biāo)點(diǎn)符號。小四號黑體二甲醚清潔燃料均質(zhì)壓燃燃燒數(shù)值模擬研究NUMERICALSIMULATIONOFHOMOGENEOUSCHARGECOMPRESSIONIGNITIONCOMBUSTIONFUELEDWITHDIMETHYLETHER四號TimesNewRoman居中加黑英文題目,三號TimesNewRoman居中加黑,一律用大寫字母,上下各空一行。ABSTRACT空一行五號TimesNewRoman,首行縮進(jìn)兩格,單倍行距。HCCI(Homogeno
4、usChargeCompressionIgnition)combustionhasadvantagesintermsofefficiencyandreducedemission.HCCIcombustioncannotonlyensureboththehigheconomicanddynamicqualityoftheengine,butalsoefficientlyreducetheNOxandsmokeemission.Moreover,oneoftheremarkablecharacteristicsofHCCIcombustionisthattheignitionandcombusti
5、onprocessarecontrolledbythechemicalkinetics,sotheHCCIignitiontimecanvarysignificantlywiththechangesofengineconfigurationparametersandoperatingconditions.InthisworknumericalschemefortheignitionandcombustionprocessofDMEhomogeneouschargecompressionignitionisstudied.ThedetailedreactionmechanismofDMEprop
6、osedbyAmericanLawrenceLivermoreNationalLaboratory(LLNL)andtheHCTchemicalkineticscodedevelopedbyLLNLareusedtoinvestigatetheignitionandcombustionprocessesofanHCCIenginefueledwithDME.ThenewkineticmechanismforDMEconsistsof79speciesand399reactions.Toconsidertheeffectofwallheattransfer,awallheattransfermo
7、delisaddedintotheHCTcode.Bythismethod,theeffectsofthecompressionratio,thefuel-airequivalenceratio,theintakechargeheating,theenginespeed,EGRandfueladditiveontheHCCIignitionandcombustionarestudied.There